 /*******************************************************************************
  * Copyright (c) 2000, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.update.internal.ui.wizards;

 import java.util.ArrayList ;
 import java.util.List ;

 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.ControlAdapter;
 import org.eclipse.swt.events.ControlEvent;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.Rectangle;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Table;
 import org.eclipse.swt.widgets.TableColumn;
 import org.eclipse.core.runtime.Assert;
 import org.eclipse.jface.viewers.ColumnLayoutData;
 import org.eclipse.jface.viewers.ColumnPixelData;
 import org.eclipse.jface.viewers.ColumnWeightData;

 /**
  * A special composite to layout columns inside a table. The composite is needed since we have
  * to layout the columns "before" the actual table gets layouted. Hence we can't use a normal
  * layout manager.
  */
 public class TableLayoutComposite extends Composite {

     private List columns= new ArrayList ();
     
     /**
      * The number of extra pixels taken as horizontal trim by the table column.
      * To ensure there are N pixels available for the content of the column,
      * assign N+COLUMN_TRIM for the column width.
      *
      * @since 3.1
      */
     private static int COLUMN_TRIM = "carbon".equals(SWT.getPlatform()) ? 24 : 3; //$NON-NLS-1$

     /**
      * Creates a new <code>TableLayoutComposite</code>.
      */
     public TableLayoutComposite(Composite parent, int style) {
         super(parent, style);
         addControlListener(new ControlAdapter() {
             public void controlResized(ControlEvent e) {
                 Rectangle area= getClientArea();
                 Table table= (Table)getChildren()[0];
                 Point preferredSize= computeTableSize(table);
                 int width= area.width - 2 * table.getBorderWidth();
                 if (preferredSize.y > area.height) {
                     // Subtract the scrollbar width from the total column width
 // if a vertical scrollbar will be required
 Point vBarSize = table.getVerticalBar().getSize();
                     width -= vBarSize.x;
                 }
                 layoutTable(table, width, area, table.getSize().x < area.width);
             }
         });
     }
     
     /**
      * Adds a new column of data to this table layout.
      *
      * @param data the column layout data
      */
     public void addColumnData(ColumnLayoutData data) {
         columns.add(data);
     }
     
     //---- Helpers -------------------------------------------------------------------------------------

     private Point computeTableSize(Table table) {
         Point result= table.computeSize(SWT.DEFAULT, SWT.DEFAULT);
         
         int width= 0;
         int size= columns.size();
         for (int i= 0; i < size; ++i) {
             ColumnLayoutData layoutData= (ColumnLayoutData) columns.get(i);
             if (layoutData instanceof ColumnPixelData) {
                 ColumnPixelData col= (ColumnPixelData) layoutData;
                 width += col.width;
                 if (col.addTrim) {
                     width += COLUMN_TRIM;
                 }
             } else if (layoutData instanceof ColumnWeightData) {
                 ColumnWeightData col= (ColumnWeightData) layoutData;
                 width += col.minimumWidth;
             } else {
                 Assert.isTrue(false, "Unknown column layout data"); //$NON-NLS-1$
 }
         }
         if (width > result.x)
             result.x= width;
         return result;
     }
     
     private void layoutTable(Table table, int width, Rectangle area, boolean increase) {
         // XXX: Layout is being called with an invalid value the first time
 // it is being called on Linux. This method resets the
 // Layout to null so we make sure we run it only when
 // the value is OK.
 if (width <= 1)
             return;

         TableColumn[] tableColumns= table.getColumns();
         int size= Math.min(columns.size(), tableColumns.length);
         int[] widths= new int[size];
         int fixedWidth= 0;
         int numberOfWeightColumns= 0;
         int totalWeight= 0;

         // First calc space occupied by fixed columns
 for (int i= 0; i < size; i++) {
             ColumnLayoutData col= (ColumnLayoutData) columns.get(i);
             if (col instanceof ColumnPixelData) {
                 ColumnPixelData cpd = (ColumnPixelData) col;
                 int pixels = cpd.width;
                 if (cpd.addTrim) {
                     pixels += COLUMN_TRIM;
                 }
                 widths[i]= pixels;
                 fixedWidth += pixels;
             } else if (col instanceof ColumnWeightData) {
                 ColumnWeightData cw= (ColumnWeightData) col;
                 numberOfWeightColumns++;
                 // first time, use the weight specified by the column data, otherwise use the actual width as the weight
 // int weight = firstTime ? cw.weight : tableColumns[i].getWidth();
 int weight= cw.weight;
                 fixedWidth+=cw.minimumWidth;
                 totalWeight += weight;
             } else {
                 Assert.isTrue(false, "Unknown column layout data"); //$NON-NLS-1$
 }
         }

         // Do we have columns that have a weight
 if (numberOfWeightColumns > 0) {
             // Now distribute the rest to the columns with weight.
 int rest= width - fixedWidth;
             int totalDistributed= 0;
             for (int i= 0; i < size; ++i) {
                 ColumnLayoutData col= (ColumnLayoutData) columns.get(i);
                 if (col instanceof ColumnWeightData) {
                     ColumnWeightData cw= (ColumnWeightData) col;
                     // calculate weight as above
 // int weight = firstTime ? cw.weight : tableColumns[i].getWidth();
 int weight= cw.weight;
                     int sparePixels= totalWeight == 0 ? 0 : weight * rest / totalWeight;
                     int newWidth = cw.minimumWidth;
                     if (sparePixels >0 )
                         newWidth += sparePixels;
                     totalDistributed += newWidth;
                     widths[i]= newWidth;
                 }
             }

             // Distribute any remaining pixels to columns with weight.
 int diff= rest - totalDistributed;
             for (int i= 0; diff > 0; ++i) {
                 if (i == size)
                     i= 0;
                 ColumnLayoutData col= (ColumnLayoutData) columns.get(i);
                 if (col instanceof ColumnWeightData) {
                     ++widths[i];
                     --diff;
                 }
             }
         }
         
         if (increase) {
             table.setSize(area.width, area.height);
         }
         for (int i= 0; i < size; i++) {
             tableColumns[i].setWidth(widths[i]);
         }
         if (!increase) {
             table.setSize(area.width, area.height);
         }
     }
 }

